Tambopata Macaw Project

Annual Report 2003

Donald Brightsmith
Duke University Department of Biology
and Rainforest Expeditions
djb4@duke.edu

ABSTRACT

The Tambopata Macaw Project is a long-term multidisciplinary study of natural history, conservation and management of large macaws and parrots. The main topics of study in the past year included monitoring and observation of Scarlet Macaw (Ara macao) nests, increasing survival rates of younger Scarlet Macaw chicks, documenting patterns of clay lick use by large macaws and other parrots, and documenting the survival and reproduction of hand-raised Scarlet Macaws in the wild in both Peru and Costa Rica. Nest monitoring found that hatching success in artificial nests is lower than in natural nests and studies to identify and eliminate the cause of this are underway. Nest observations and clay lick observations have shown that parrot and macaw activity is severely reduced by rain and that this may have important implications for chick growth, foraging and parrot ecology in general. Seasonal changes in lick use are drastic as the most active month (August) has over ten times more lick use than the least active month (May). The differences in lick use may be related to a mixture of seasonal migration away from the area by some species and changes in resource quality and abundance throughout the year. Studies are underway to unravel the relative roles of these mechanisms. The analysis of three different Scarlet Macaw release projects from Peru and Costa Rica have shown that hand-raised macaws survive at a surprisingly high rate (74% first year and 96% post first year). This finding provides hope for future attempts to reestablish wild populations of macaws using captive breeding stock.

INTRODUCTION

Large macaws are endangered or declining throughout most areas where they occur due to a combination of hunting, habitat loss, and collection for the pet trade (Juniper and Parr 1998, Snyder et al 2000, Wright et al 2001). Unfortunately the basic biology of most macaw species is still poorly known which makes their conservation difficult. From 1989 - 1993 researchers at Tambopata Research Center in se Peru conducted research on basic macaw biology and developed management techniques to increase the reproductive success of large macaws (Nycander et al 1995). The current study, started in 1999, is a continuation and expansion of these earlier investigations and includes work on a broad range of topics including basic macaw biology, macaw management techniques, ecology of clay lick use and impacts of ecotourism. The clay lick work has been carried out at the riverbank located approximately 300 m from the lodge where 16 species of parrots and 8 other species of birds have been recorded eating clay. The clay apparently provides birds with sodium and protection against the toxins in their diets (Brightsmith and Aramburú submitted, Gilardi et al 1999). The macaw management work has focused on evaluating the success of nest boxes versus natural tree cavities and the development of supplemental feeding protocols that increase the survival chances for second and third chicks, as these often starve if not aided. The project also continues to documents the survival and reproduction of the macaws that were raised and released at the research center in the early 1990's. As Tambopata Research Center has become a successful tourist lodge, the project is monitoring the effects of ecotourism especially at the clay lick where the potential for disturbance is high. The following report is a brief summary of the main research topics that have been investigated in the past year and the most noteworthy results.

OBJECTIVES

Nest monitoring

Known and suspected macaw nest sites are checked every 1 - 7 days with the goal of documenting macaw nesting ecology and nesting success. The specific objectives are:

1) Compare hatching success between natural and artificial nests
2) Compare predation rates and fledging success between natural and artificial nests
3) Document chick growth patterns in nests with different numbers of chicks

Chick survival

Although up to 4 chicks may hatch in a nest, only one or two chicks usually survive. The goal of this section is to document the starvation of young macaws and develop supplemental feeding methods to increase their survival.

Nest observations

Document the nest attendance patterns of adult macaws at nests and its change throughout the nesting season. Compare the rates of arrival and nest attendance patterns between nests with one chick and nests with > 1 chick.

Patterns of clay lick use

Document the daily, seasonal, and annual patterns of clay lick use by parrots, macaws and other species.

Clay lick ecotourism impacts

Determine if the presence of tourists has a negative impact on the birds using the clay lick and how to reduce such impacts.

Survival and reproduction of hand-raised macaws

Document the survival and reproductive efforts of the macaws that were saved from starvation and hand-raised at TRC from 1991 - 1995. These data have been combined with those from two similar studies in Costa Rica to determine what factors facilitate survival of released Scarlet Macaws.

METHODS

The study site is Tambopata Research Center in southeastern Peru. To determine the relative success of macaws in natural and artificial nests we climb the nests regularly (every 1-7 days) and count the number of eggs and chicks. We also weigh and measure the chicks. To study and enhance chick survival we climb nests with young chicks up to two times per day. If we find that younger siblings are not gaining weight normally we feed them and return them to the nest. For nest observations pairs of observers watch the nest from 5 AM - 11:30 AM and 11:30 AM - 5:30 PM and record the arrivals and departures of the parents. They also record alarm calls and interactions with predators and other macaws. The presence of hand-raised macaws is recorded when they arrive in the lodge or when they are seen at nests during nest revisions. At the clay lick, observers scan the lick every five minutes from sunrise until about 7:00 AM and record the weather and count all birds that are consuming the clay. The observers also record the passage of boats and the quantity of tourists in the area.

RESULTS

Nest monitoring

Data from nest monitoring show that natural, PVC, and wooden nest boxes all have vastly different hatching success rates (Table 1). Natural nests have a hatching success rate of 65% while the PVC nest boxes commonly used around TRC have hatching rates of only 41%. The hatching rates in wooden boxes may be higher (80%) but the sample sizes are too small to draw any conclusions. By comparison the survival of chicks in all three types of nest boxes is surprisingly similar (Table 2).

Table 1: Scarlet Macaw nest fate during the egg stage in different nest types at Tambopata Research Center, Peru. Data are from four field seasons (Nov 1999- Jan 2003).

Table 2: Scarlet Macaw nest fate during the chick stage in different nest types at Tambopata Research Center, Peru. Data are from four field seasons (Nov 1999- March 2003). Natural nest data are from Nycander et al (1995), supplemented with my data from 2000-2003.

Chick survival

Twenty four percent of all Scarlet Macaw chicks monitored (9 of 37) died of starvation or would have if the researchers had not intervened. All of these were younger chicks in nests with 2 - 4 nestlings in total. Eight of 9 (88%) died within one week of hatching. At the time of death, their oldest sibling weighed on average 500% more than the dieing chicks. The difference in chick age may be important in chick survival as two chicks survived in nests where the age spread was < 3 days and only one chick survived in nests where the spread in hatching was > 5 days. These findings suggest that sibling competition and not the overall food supply may be the determining factor in chick survival, but larger sample sizes are needed to confirm these preliminary findings

Supplemental feeding techniques have proved successful at helping some younger chicks survive, but not all. Four of 5 second hatched nestlings that would have starved were saved through supplemental feeding. These birds usually needed to be fed only 1 - 3 days and then the parents resumed feeding and the chicks were able to fledge with no further assistance. Third hatched chicks were not as successful: both died within a week in spite of the supplemental feedings received.

Nest observations

Nests where parents are feeding two chicks average 0.86 ± 0.50 visits per hour (N = 4) and nests with one chick average 0.6 ± 0.19 (N = 4). Rain cuts the visitation rate from 1.03 visits per hour to 0.38 visits per hour indicating that this is likely having significant impacts on the feeding rate and possibly on chick growth.

Patterns of clay lick use

This year work at the clay lick intensified and detailed analysis of 606 mornings worth of observations began. Most species of parrots (9 of 14) use the lick almost exclusively before 7:30 AM. The others use the lick at nearly any time of the day. This latter group includes the three large macaws: Scarlet, Blue-and-yellow and Red-and-Green. Macaws and parrots use of the clay lick at TRC is highly sensitive to weather conditions. Fog and rain both greatly reduce total lick use. On average each 5 minutes worth of rain recorded in the early morning reduces lick use by 5% (± 1%). Similarly each 5 minutes of fog reduces lick use by approximately 3% (± 0.5%) (Brightsmith in prep a). On days with rain during the early morning (4:00 - 7:30 AM) many species of parrots do not use the lick even if the rest of the day is clear and sunny. The seasonal changes in lick use are very pronounced (Table 3). Lick use peaks in August and remains high through December then begins to drop until it hits its lowest point in May (Brightsmith in prep b).

Table 3. Monthly averages and standard deviations for total early morning bird use at the Tambopata Research Station clay lick. The averages and standard deviations are in bird minutes (3 birds on the lick for 10 minutes each = 30 bird minutes). The data are from 606 mornings between January 2000 and November 2002.

Clay lick ecotourism impacts

The number of birds at the lick is not correlated with the number of people observing the lick (p>0.05 for all species based on 191 mornings of clay lick observations Multiple regression analyses). This means that approximately the same number of birds go to the clay lick regardless of the number of people watching the birds.
Survival and reproduction of hand-raised macaws
Across the three studies summarized (two in Costa Rica and the one in Peru) a total of 71 Scarlet Macaws have been released. The combined first-year survival post release was 74% and the post first-year survival was 96%. Predation rates were very low despite great differences in the diversity and abundance of predators at the sites. Birds from larger releases conducted after a core flock became established had higher survival rates. Breeding attempts have been recorded at all three sites and hand-raised birds with wild mates have successfully fledged young in Peru. Supplemental feeding post release played an important role in establishing a core flock at all three release sites (Brightsmith et al in prep).

DISCUSSION

In the past year we have greatly advanced our understanding of a wide range of topics relating to the natural history and conservation of large macaws and parrots. Management techniques under study include the use of nest boxes, supplemental feeding of starving chicks and reintroduction of Scarlet Macaws. Nest monitoring work has shown that hatching success is lower in artificial nests than natural nests. The working hypothesis is that higher temperatures and lower humidity in artificial nests is causing the low hatching, and studies testing this hypothesis are underway. Work with young chicks has shown that most younger chicks that die of starvation do so in the first weeks of life when the percent weight difference between siblings is highest. Supplemental feeding can save most second chicks from starvation. However two feedings a day is probably not sufficient to facilitate the survival of three chicks from a nest at this site, but our sample sizes are still too small to draw conclusions. The summaries of reintroduction work from Peru and Costa Rica have definitively shown that hand-raised Scarlet Macaws can survive in the wild. In fact the survival rates of 74% first year and 96% post first year are extremely high for any sort of reintroduction work. The analyses show that larger releases (12+) are much more successful than small releases (Brightsmith et al in prep). The fact that birds in Peru are successfully reproducing and birds at both sites in Costa Rica are attempting to breed suggests that it may be possible to use captive stock to establish new wild populations.

Nest observations have shown that Scarlet Macaw activity is greatly reduced by rain. This will provide important background information for analyses of chick growth and survival. The data suggest that pairs with two chicks or more chicks make more visits to the nest, but greater sample sizes are needed before we can make meaningful statistical comparisons between these two nest types. Documenting the change in adult behavior with two chicks is an important part of our study, as we must know the effects on the parents of aiding the survival of younger chicks. Further analysis of these data is scheduled for June - September 2003.

The 606 mornings of clay lick data contain 307,000 registrations and may be the largest data set on parrots ever assembled. This is the first time that patterns of lick use have been so completely documented for any group of species, bird or mammal. The finding that some species entirely forgo lick use on days with early morning rain was unexpected and suggests that failure to eat soil does not have strong negative short-term consequences. Lick use is greatly reduced by both rain and fog and is highly variable by season. A model including rain, fog, sun and season explains approximately 40% of the variation in total lick use (Brightsmith in prep a). It has been suggested that censuses at clay licks may be useful to detect changes in parrot populations in rain forest environments where parrots are notoriously hard to census (Snyder et al 2000). The current analysis suggests that such censuses would be able to detect changes in lick use of 20% or more and therefore could serve as a bellwether for parrot population decline (Brightsmith in prep a). The use of the clay lick peaks in the late dry season and then drops off precipitously as the wet season progresses. These changes are likely due to the changes in the quality and or abundance of food. Studies attempting to explain these marked seasonal patterns are currently underway. A 12 month censuses of the parrots is being conducted Jan 2003 - Jan 2004 to determine if parrots are leaving the area and how this may be effecting lick use. In Nov 2003 work will begin to document the nutrient and toxicity levels of foods available to the birds in different seasons. These studies coupled with the detailed descriptions of the seasonal trends currently underway (Brightsmith in prep b) should provide us with a much greater understanding of why birds eat soil.

The preliminary analyses of the number of birds and the number of tourists observing the lick at TRC suggest that the act of observing the birds does not reduce the number of birds that visits the lick. The tourists are kept together and relatively quiet at a distance of 150 m or more from the lick. These results suggest that the protocol in use by Rainforest Expeditions is not causing major reductions in the number of birds using the lick, but additional analyses are needed to determine if there are more subtle impacts on the birds. Further analyses will include the reaction of birds to boats and whether or not the birds shift to parts of the lick to be farther from groups of observing tourists.

OTHER ACCOMPLISHMENTS

Work continued this year with the Native Community of Infierno. The project provided employment and training for five members of the community and provided information to the community as a whole. I also worked as an instructor for the guide course for the Native Community of Infierno and the guide course for Rainforest Expeditions. Through these courses I was able to share my knowledge of tropical ecology and conservation with the next generation of young Peruvian guides. Of note is that many of the people in these courses will become the next generation of leaders in the native community and leaders or educators in Peru. I have also been working with government representatives who are drafting recommendations on how to manage tourism and implement long-term monitoring schemes at clay licks. I also gave talks to local groups in Peru, bird clubs in the US and scientific meetings.

ACKNOWLEDGMENTS

Special thanks to all the assistants who have worked on the project over the past year. Without them the hundreds of nest climbs and thousands of hours of clay lick and nest observations would be impossible. In particular I would like to thank the field leaders Adriana Bravo, Andrea Johnson, Aida Figari and Oscar Gonzales for their help and leadership. Thanks also to Kurt Holle, Eduardo Nycander, Luis Zapater, Mario Napravnik, Mariana Elias, Ricardo Tenaud, Jose Portocarrero and the rest of the staff of the Posada Amazonas, Tambopata Research Center and Rainforest Expeditions for all their support and help with project logistics. Thanks also to Reuben Bazán of the soil lab at Universidad Nacional Agraria La Molina for his help with soil analyses. Thanks also to Darrel Stiles, Dominique Homberger, Katherine Renton and Ethel Villalobos for reviewing manuscripts and providing helpful advice. Thanks also to the Raleigh-Durham Caged Bird Society, Janice Boyd and Willard and Lucille Smith for their continued support. And finally, thanks to EarthWatch for providing the funding and manpower for making this work possible.

Literature Cited

(see also recent publications below)

Juniper, T., and M. Parr 1998. Parrots: A Guide to Parrots of the World. Yale University Press, New Haven.

Nycander, E., D. H. Blanco, K. M. Holle, A. d. Campo, C. A. Munn, J. I. Moscoso, and D. G. Ricalde. 1995. Manu and Tambopata: nesting success and techniques for increasing reproduction in wild macaws in southeastern Peru. Pages 423-443 in J. Abramson, B. L. Spear, and J. B. Thomsen, editors. The Large Macaws: Their Care, Breeding and Conservation. Raintree Publications, Ft. Bragg, CA.

Snyder, N. F. R., P. Mc Gowan, J. Gilardi, and A. Grajal. 2000. Parrots. Status survey and conservation action plan 2000-2004. Page 180 pp. IUCN, Gland, Switzerland and Cambridge, UK.

Wright, T. F., C. A. Toft, E. Enkerlin-Hoeflich, J. Gonzalez-Elizondo, M. Albornoz, A. R. Ferraro, F. Rojas-Suarez, V. Sanz, and e. al. 2001. Nest poaching in Neotropical Parrots. Conservation Biology 15:710-720.

RECENT PUBLICATIONS

Scientific Journal Articles

Brightsmith, D., and R. Aramburu. Submitted April 2003. Avian geophagy in Southeastern Peru: the roles of soil characteristics in soil choice. Biotropica.

Brightsmith, D., J. Hilburn, A. Del Campo, J. Boyd, M. Frisius, R. Frisius, D. Janik, and F. Guillén. Submitted Aug 2003. Survival and reproduction of hand-raised Scarlet Macaws (Ara macao) in the wild. Biological Conservation.

Brightsmith, D. Submitted Aug 2003. Effects of weather on avian geophagy in Tambopata, Peru. Wilson Bulletin.

Brightsmith, D. J. Submitted Aug 2003. Community-wide patterns of parrot nesting in the southwestern Amazon Basin. Wilson Bulletin.

Popular Articles

Johnson, A. and D. Brightsmith. In press. Macaw Conservation in the Native Community of Infierno. Psittascene. Newsletter of the World Parrot Trust.

Brightsmith, D. October 2003. The real dirt on Parrot Clay Licks. Bird Talk Magazine.

Wilson, J. and D. Brightsmith. July 2003. The battle for Amor. Bird Talk Magazine. This article documents the fight over a nest between a pair of Scarlet Macaws and a pair of Red-and-green Macaws at my research site in Peru.

Brightsmith, D., February 2003. My macaws. Ranger Rick Magazine. This is an discussion of my research written for young children with photos by Teo Allofs.

Brightsmith, D., August 2002. What eats parrots? Bird Talk. This is a discussion of the species of predators that eat parrots in the wild.